A Brass Movement F.P. Journe Chronomètre à Résonance, Reference R

The Chronomètre à Résonance is of all the watches invented by F.P. Journe, perhaps the one that stands out as the most genuinely unique in his body of work. This is not to diminish his other accomplishments, which are considerable, but the Chronomètre à Résonance represents a complication which, since its invention by Breguet in the late 18th, had remained untouched by watch and clockmakers until Journe decided, in the 1980s, to attempt to construct a resonance watch based on Breguet’s principles.

The project was not fully realized until 1999, when François-Paul presented the first working Chronomètre à Résonance, and the Resonance Chronometer we have today is a very early model, with a rhodium-plated brass movement.

Brass movements are a tell-tale to collectors of early production Journe watches, as fairly soon after launching his brand, Journe began to switch over to using rose gold for his movement plates and bridges. In either metal, the movement Journe used for his resonance watches was the caliber 1499, which was eventually replaced by the caliber 1520, in 2020. The main difference between the two movements is that the 1520 includes the addition of two remontoirs on each of the independent going trains.

The basic idea behind the Chronomètre à Résonance has been described many times, with varying degrees of success, but the basic principle is fairly straightforward. A watch or clock taking advantage of the resonance phenomenon should have better precision than a conventional timepiece; greater precision is the goal and purpose of a resonance watch.

Resonance simply means the tendency for two oscillators, if they share the same natural frequency, to begin to beat in synchrony with each other. They may swing in the same direction, or in opposite directions, depending on how they are mechanically coupled to each other. Galileo had noticed this phenomenon in his study of pendulums, and was working on a design for a resonance pendulum clock at the time of his death. The great French horologist Antide Janvier created several resonance pendulum clocks, and shortly thereafter, Breguet, who knew Janvier and his work, applied the same principle to pocket watches. The next time anyone showed a resonance watch would be almost 200 years later, when Journe introduced his first Resonance Chronometer.

In a double oscillator resonance system, the two oscillators (balance or pendulum) will tend to begin to beat synchronously because they share energy via some mechanical connection – in Journe’s watches, as in Breguet’s, the tiny forces produced by the balance springs as they expand and contract, influence each other and since synchronous oscillation is a preferred (efficient) energy state, the two oscillators will tend to settle into synchrony with each other. This sharing of energy is also the reason that a resonance watch should be more precise. If one of the balances for some reason begins to run either fast or slow, energy will be transferred between the two balances which should reduce the error by half. The entire system thanks both to this phenomenon, and to increased amount of energy compared to a watch with a single oscillator, should make resonance watches more stable in their rate.

So why is every watch not a resonance watch? There are a couple of reasons; first of all, resonance timepieces are expensive and difficult to construct. Not only to they have to be made very precisely and designed in such a way as to enhance the resonance effect, the two balances must be adjusted so that they are very close to each other in rate; in a Journe Resonance Chronometer, the two balances must be adjusted so that they are running with no more than five seconds per day difference between them. The second reason is that single balance watches can (obviously) give excellent results; Rolex makes around a million watches a year that run at ±2 seconds per day.

None of which takes away in the slightest in the level of sophistication in Journe’s Chronomètre à Résonance. The fact that Journe was able to take an obscure but fascinating moment in the much larger history of Breguet’s work, understand its fundamental principles, and make them work again in a modern wristwatch, has got to rank as one of the most intellectually, historically, and even emotionally important events in modern watchmaking.

This particular Chronomètre à Résonance was made in 2002, and the movement as we have noted, is one of the early brass movements, rhodium-plated, caliber 1499 (with the rose gold version entering production two years later, in 2004). The layout is derived directly from the configuration adopted by Breguet for his resonance pocket watches, with the balances situated close to each other on the movement plate in order to allow energy to be transferred as efficiently as possible. The physical proximity of the balance rims to each other has prompted speculation over the years that the balances are oscillating synchronously thanks to air turbulence, but Breguet ruled this out by inserting steel barriers around his balances; Journe did the same. In both instances, the resonance effect still occurred.

This Reference R Chronomètre à Résonance has a classically proportioned 38mm platinum case, and, like all early Journe brass movement watches, it represents a moment of great importance in modern horology – a moment when a beautiful idea which had lain dormant for almost two hundred years, had new life breathed into it, after nearly twenty years of work, by F.P. Journe.

See it here